Tissue distribution and biliary excretion of BAPTA-AM liposome for injection in rats

AIM To investigate the tissue distribution and biliary excretion of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(actoxymethyl ester)(BAPTA-AM)liposome in rats.METHODS Twenty-four Sprague-Dawley rats were randomly divided into four groups with six rats for each group.BAPTA-AM liposome dissolved in physiological saline was administered to different groups of rats by tail vein at a dose of 3.0 mg·kg-1.Tissue homogenates of experimental animal were made at 10 min,1.5 h and 9 h after administration.Bile samples were collected from bile cannulated rats at each interval after administration.The concentration of BAPTA-AM in rat tissue homogenates and the concentration of BAPTA in rat bile were quantified,respectively.RESULTS After i.v.injection of BAPTA-AM liposome 3.0 mg·kg-1 to rat,the parent drug concentrations in tissues were higher than those in plasma at the same time.Parent drug was mainly distributed in lung,liver,spleen and kidney.The BAPTA-AM concentrations were reduced significantly at 9 h after dosing in most tissue.After i.v.injection of BAPTA-AM liposome injection,the biliary excretion rate of BAPTA was slowly,and cumulative biliary excretion did not plateau during the 12 h collection period.CONCLUSION After intravenous injection,BAPTA-AM liposome is rapidly distributed into tissue in rat and is eliminated via biliary excretion of BAPTA.